JP3098702B2 - Racket string and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a string for rackets, such as tennis, badminton, and squash, which has excellent hitting characteristics and durability.

[0002]

2. Description of the Related Art Conventionally, strings for rackets such as tennis, badminton, and squash (strings are also referred to as "guts") are made of natural guts mainly composed of cattle intestines because of their excellent playability. I was However, since this gut is cut off in a short time use, and has insufficient durability and is expensive,
In recent years, its usage has been gradually decreasing.

[0003] The current major strings are made of monofilaments of synthetic fiber (Synsatech). This string is good in terms of durability and price, and is still very popular. However, recently, the demand level of players has increased and the racket has been mainly made of carbon fiber reinforced resin having high rigidity, so that demands for more excellent hitting properties and soft strings have been increasing.

For this reason, multifilament strings have been developed in place of synthetic filament (Synsatech) monofilaments, and have begun to be used in popularity. The present inventors have also proposed a novel multifilament string (Japanese Patent Publication No. 4-23551). Strings of this type are gaining popularity in Japan and around the world, and their production is increasing.

[0005]

However, the durability of the string made of multifilament is superior to that of natural gut but is not as good as that of monofilament.
In addition, the price is halfway between the two, and there is a strong demand for improved durability. In addition, the stretchability of stringing the racket is also between monofilament and natural gut,
These improvements were also requested.

In order to solve the above-mentioned conventional problems, the present invention has excellent hitting properties, gives a soft and pleasant hit feeling to a player, does not break even after a long use, has excellent durability, and has an excellent tension. It is an object of the present invention to provide a racket string excellent in installation property and a method of manufacturing the same.

[0007]

To achieve the above object, a racket string according to the present invention is characterized in that a multifilament made of synthetic fiber is fixed by an inner layer resin, and the surface thereof is coated with a resin coating layer. An inner layer resin fixing the multifilament is an adhesive composition containing an ultraviolet or radiation curable adhesive and an anaerobic adhesive. With such a configuration, the ultraviolet ray or radiation curable adhesive of the inner layer resin, and the adhesive composition containing the anaerobic adhesive, the multifilaments can be bonded and integrated as a whole, so that the durability was excellent. Things. That is, the surface layer portion of the multifilament is mainly fixed by an adhesive composition containing an ultraviolet or radiation curable adhesive, and the inner layer portion is mainly fixed by an adhesive composition containing an anaerobic adhesive. The part from the surface layer to the core is bonded and integrated with the cured resin. For this reason, it does not break even when used for a long time, and is excellent in durability. In addition, since the string uses a multifilament, it has excellent hitting properties, gives the player a pleasant hit feeling with softness, and also has excellent stretchability. In the above, the anaerobic adhesive refers to a polymerizable resin composition that maintains a liquid state in the air and cures when the air is shut off.

[0008] In the above string, the adhesive composition of the inner layer is an ultraviolet or radiation curable adhesive: 30 to 9
5% by weight and anaerobic adhesive: preferably 5 to 70% by weight. In the string,
When the adhesive composition of the inner layer is composed of an ultraviolet or radiation curable adhesive: 70 to 90% by weight, and an anaerobic adhesive: 10 to 30%
More preferably, it is constituted by weight%.

In the above string, it is preferable that the anaerobic adhesive is a composition containing a methacrylate compound as a main component. In the string, it is preferable that the amount of the adhesive composition in the inner layer is in the range of 15 to 35% by weight of the entire string.

In the string, the resin coating layer on the surface is preferably made of a nylon resin. In the string, the amount of the resin coating layer on the surface is preferably in the range of 15 to 45% by weight of the entire string.

In the string, it is preferable that an inorganic filler is added in a range of 1 to 30% by weight to a resin coating layer on the surface. A more preferable addition amount of the inorganic filler is in a range of 3 to 15% by weight. When the inorganic filler is added to the resin coating layer on the surface, it is possible to prevent the strings from being worn due to the friction of the contacts of the strings stretched vertically and horizontally at the time of hitting the ball, and to further improve the durability.

Further, in the string, it is preferable that the inorganic filler is in the form of whiskers or particles. In the string, the inorganic filler is
It is preferably in the form of whiskers or particles of aluminum borate and contained in an amount of 3 to 15% by weight. Aluminum borate, for example, is less colored and slightly turbid when added to a nylon resin, but is also excellent in transparency.

In the string, it is preferable that the multifilament made of synthetic fiber is a polyamide synthetic fiber. This is because the strength is high and the stretchability is excellent. Next, the method for producing a racket string of the present invention is as follows.
A method for producing a racket string in which a multifilament of synthetic fibers is fixed with an adhesive and a resin coating layer is coated on a surface thereof, wherein the multifilament includes an ultraviolet or radiation curable adhesive, and an anaerobic adhesive. A multi-filament is twisted, and the adhesive part close to the surface layer of the string is cured by irradiating ultraviolet rays or radiation as a first-stage curing treatment, and then as a second-stage curing treatment. It is characterized in that an adhesive portion inside the string is cured, and thereafter, a coating resin is applied to the surface to form a resin coating layer. By adopting such a manufacturing method, the string of the present invention can be efficiently and rationally manufactured. In the above, the term “ultraviolet rays” refers to electromagnetic waves having a wavelength of about 100 to 400 nm. Radiation refers to α rays, β rays, γ rays, X rays, electron beams, and the like.

In the above method, it is preferable that the second-stage curing treatment is a treatment that is left at room temperature for 1 hour or more. This is to cure the core of the multifilament.

In the above method, the method of applying an adhesive composition for fixing the multifilament, twisting the multifilament, and performing the first-stage curing treatment is as follows.
It is preferable that the adhesive composition is impregnated with the untwisted multifilament, and then the first-stage curing treatment is continuously performed until the multifilament is twisted and wound. When the non-twisted multifilament is impregnated with the inner layer adhesive composition, the adhesive composition can be applied to the inside of the multifilament. Thereafter, by irradiating the multifilament with ultraviolet rays or radiation until it is wound while being twisted, the multifilament can be efficiently manufactured in a series of steps. In particular, ultraviolet irradiation is preferable because it is safe and the equipment cost is low.

In the above method, the multifilament is impregnated with the adhesive composition for the inner layer and then squeezed to adjust the amount of the adhesive composition to be in the range of 20 to 40% by weight. Is preferred. By squeezing the adhesive composition for the inner layer, the amount of adhesion of the adhesive composition can be accurately controlled. When the amount of the inner layer adhesive composition adhered is in the range of 20 to 40% by weight, since the resin coating layer on the surface does not exist at this stage, the parameter is the sum of the multifilament and the inner layer adhesive composition. is there. When the entire string of the final product is used as a parameter, the amount of the adhesive composition for the inner layer becomes 15 to 35% by weight.

In the above method, the anaerobic adhesive is preferably a composition containing a methacrylate compound as a main component. In the above method, the adhesive composition containing the radiation-curable adhesive and the anaerobic adhesive is composed of 30 to 95% by weight of the radiation-curable adhesive and 5 to 70% by weight of the anaerobic adhesive. Preferably.

In the above method, it is preferable that an inorganic filler is added to the resin coating layer on the surface in a range of 1 to 30% by weight. In the above method,
The resin coating layer on the surface is preferably a nylon resin.

In the above method, it is preferable that the multifilament made of synthetic fiber is a polyamide synthetic fiber.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to the drawings. FIG. 1 is a cross-sectional view of one embodiment of the string of the present invention. In FIG. 1, 1 is a racket string, 2 is a surface portion of the multifilament, 3 is a central portion of the multifilament, 4 is an inner resin layer applied when twisting the multifilament, and 5 is a surface resin coating layer.

The inventors of the present invention have systematically considered that a racket string comprising a multifilament, particularly a string obtained by curing and fixing a multifilament with an ultraviolet curable adhesive, has lower durability than a monofilament.
The present inventors have studied the present invention in detail and arrived at the present invention. That is, as a result of investigating the behavior of the string being worn in detail, the wear rate is determined by the surface resin coating layer 5 and the plurality of fibers in the multifilament fiber (center layer) 3 of the plurality of polyamide synthetic fibers shown in FIG. It was found that the size was extremely larger than that of the multifilament fiber (surface layer) 2 of the polyamide synthetic fiber. Separately, the curing status of the multifilament fiber (center layer) and the multifilament fiber (surface layer) was also analyzed. As a result, it was found that unreacted monomer was present in the multifilament fiber (center layer), and curing was not sufficiently performed. Probably, in normal irradiation, the ultraviolet ray does not sufficiently reach the center of the string, hardening and fixing are not sufficient, and it is presumed that the wear rate increases.

Therefore, to improve the durability, two methods are conceivable: a method of further increasing the abrasion resistance of the surface and a method of curing the central layer to the same degree as the surface layer. An invention based on the former idea has already been proposed (Japanese Patent Application No. 7-1).
01825). The present invention is an invention developed from the latter idea. That is, when an ultraviolet or radiation-curable adhesive and an anaerobic adhesive are combined and irradiated with ultraviolet or radiation, the surface is cured in the same manner as in the prior art, and if left for a while, the surface is cured. Found that the anaerobic adhesive activated and cured, and eventually cured to the same extent as the surface.

The string manufactured in this way is
It was also newly found that they exhibited the same durability as conventional monofilament products. Also, since the center of the string is hardened, the tension and waist of the entire string are moderately improved,
As a result, the stretchability was also improved.

Next, FIG. 2 is a process chart for explaining an embodiment of the manufacturing method of the present invention. This process is
Filament unwinding step 10 and inner layer resin applying step 2
0, an ultraviolet or radiation irradiation step 30, and a twisting and winding step 40. Although not shown, after this process, there is a step of coating, for example, hot-melt nylon 66 to perform surface resin coating. This surface resin coating method is performed by passing a string through a crosshead die of an extruder. In the filament unwinding step 10, for example, a multifilament 12 made of, for example, a nylon-based synthetic fiber is unwound and drawn out from a yarn package (winding body) 11 and aligned with a guide 13 to form a non-twisted multifilament yarn 14. I do.

Next, in the inner layer resin application step 20, the inner layer adhesive composition containing an ultraviolet or radiation curable adhesive and an anaerobic adhesive placed in the resin solution tank 26 is used.
Then, the non-twisted multifilament yarn 14 is immersed through the guides 21, 22, 23, 24. Thereafter, by passing through the nozzle 25, the adhesive for the inner layer is squeezed to control the adhesive amount to a constant value. The nozzle 25
On the more upstream side, the multifilament yarn 14 is in a non-twisted state, and on the downstream side from the nozzle 25, twisting is performed as shown by the arrow B.

Next, in the ultraviolet ray or radiation irradiation step 30, ultraviolet ray or radiation is applied. For the sake of explanation, taking ultraviolet irradiation as an example, a high-pressure mercury lamp 32 is installed in a lamp house 31, and when a twisted multifilament yarn 33 passes through the inside of the lamp house 31,
The adhesive on the surface layer of the multifilament (portion 2 in FIG. 1) is cured.

Next, in the twisting and winding step 40,
Multifilament yarn 46 in which surface layer adhesive is cured
Is taken up inside the twisting / winding machine 42, where the tension is adjusted by passing through a guide roll 43, further passed through a traversing roll 45 and wound up by a winding roll 44.
Since the take-up roll 44 is rotating as indicated by the arrow A, a real twist is added to the multifilament yarn 46 provided with the inner layer resin. In this state, the multifilament yarn 46 is cured and fixed in the lamp house 31, and the constituent filaments are bonded to each other. At the same time, the torque due to twisting is fixed and stabilized.

As the polyamide-based synthetic fiber used in the present invention, nylon 6, nylon 66 or a copolymer thereof is preferable, since particularly high strength is easily obtained. In order to obtain a soft feeling at the time of hitting the ball, it is desirable that the fiber showing the thickness of the single fiber be 2 to 9 denier. Strength is 5 g / denier or more and elongation is 10 to 30% from the viewpoint of durability.
A degree is desirable. Further, in order to obtain a strong, round cross-sectional shape and a soft feeling, the number of twists applied to the entire yarn is preferably about 50 to 300 turns / m.

Next, among the composite adhesives used at the time of twisting, basically, an arbitrary ultraviolet curable adhesive is used as the ultraviolet curable adhesive. The ultraviolet curable adhesive may be any one containing a photopolymerizable prepolymer, a photopolymerizable monomer and a photopolymerization initiator, and in addition, a sensitizer, a pigment, a filler, an inert organic polymer, a leveling agent, It may contain a thixotropic agent, a thermal polymerization inhibitor, a solvent and the like.

Examples of the photopolymerizable prepolymer include polyester acrylate, polyurethane acrylate, epoxy acrylate, polyether acrylate, oligoacrylate, alkyd acrylate, and polyol acrylate.
Polyurethane acrylates and epoxy acrylates are desirable, and polyurethane acrylates are most desirable from the viewpoint of softness and resilience. This polyurethane acrylate can be obtained by reacting a compound having an isocyanate group such as tolylene diisocyanate with an acrylate having a hydroxy group such as a 2-hydroxy group. In addition, a characteristic urethane acrylate can be obtained by a combination of a diisocyanate, a diol, a dibasic acid, and an acrylate compound.

The photopolymerizable monomer is useful as a crosslinking agent and a diluent, and various acrylates are mainly used. The above-mentioned various acrylates become a polymer having a urethane binding group having an excellent affinity for polyamide in a very short time upon irradiation with ultraviolet light, and thus exhibit an excellent adhesive with various nylons which are polyamide-based synthetic fibers.

Examples of the photopolymerization initiator include sulfur compounds, acetophenones, and carbonyl compounds such as benzophenone. Of the composite adhesive used for twisting,
The other anaerobic adhesive is a composition which usually exhibits a liquid state in contact with air or oxygen, but rapidly polymerizes, cures and adheres when cut off from air or oxygen.

Generally, the anaerobic adhesive is mainly composed of a monomer which can be anaerobically polymerized, a polymerization initiator which is a latent catalyst, and a polymerization inhibitor for stabilizing the resin during storage. In addition, it may contain a polymerization accelerator, a stabilizer, a viscosity adjuster, an adhesive strength adjuster, a colorant, and the like. The anaerobically polymerizable monomer is, for example, a compound represented by the following chemical formula (Chem. 1 to 6) and an acrylate monomer.

[0034]

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[0035]

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[0036]

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[0037]

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[0038]

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[0039]

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The polymerization initiator which is a latent catalyst is mainly composed of an organic peroxide such as cumene hydroperoxide, benzoyl peroxide or methyl ethyl ketone hydroperoxide. Further, polymerization catalysts such as hydroperoxide / phosphorus compound and orthosulfobenzoimide / mercaptan are also known.

As the polymerization inhibitor, quinones such as benzoquinone are known. The mixing ratio of the anaerobic adhesive to be added to the ultraviolet-curable adhesive is 5/70%, preferably 10 to 30%, based on the weight of the ultraviolet-curable adhesive.

When the amount is less than 5%, the effect of improving durability is small, and it is desirable that the amount is 5%, preferably 10% or more. If the blending amount is 70% or more, the hardness of the string becomes large, and the elongation of the string at the time of hitting the ball cannot follow the elongation of the multifilament of the polyamide-based synthetic fiber. It is not suitable for the purpose of the present invention. Therefore, the compounding ratio of the anaerobic adhesive is 70%.
% Or less, preferably 30% or less.

[0043] Then the preferred borate made of aluminum whiskers or particles used in the present invention, if Shimese by Formula is _{9AL 2 O 3 · 2B 2 O} 3, whiskers average fiber length 10 to 30 [mu] m, average fiber The diameter is 0.5-1.
0 μm, and the particles have an average particle diameter of 3 to 100 μm.

When the amount is less than 1% by weight, the effect is hardly obtained, and preferably 1% by weight or more. Also, 30
If it is more than 10% by weight, the whole string becomes hard and is not suitable for the soft ring which is the object of the present invention. These effects not only improve the durability of the string, but also improve the stretchability, probably due to the smoothing of the surface. Aluminum borate is particularly useful because it has a lower index of refraction than other materials and can provide a transparent string.

An ultraviolet curable adhesive and an ultraviolet curable adhesive are added to the multifilament of the polyamide synthetic fiber.
Using a composite adhesive compounded at a ratio of 70% by weight, preferably 10 to 30% by weight of an anaerobic adhesive, and twisting a multifilament in a state where the resin is impregnated, as a first-stage curing treatment using ultraviolet rays Irradiate to cure each single fiber firmly in a short time. The composite adhesive is an adhesive having a configuration as described in detail above. After impregnation to control the application amount of the composite adhesive, it can be squeezed through a nozzle or the like. UV light is about 100nm to 400nm
Refers to light with a wavelength in the range of
In particular, the light has a wavelength in the range of about 200 nm to 400 nm. Examples of the light source include a mercury lamp, a xenon lamp, a carbon arc, a plasma arc, and a metal halide lamp, and a high-pressure mercury lamp and a metal halide lamp are particularly useful from the viewpoint of curing efficiency. Although a metal halide lamp is more suitable for curing a thick film, it is not sufficient to achieve the object of the present invention. As the ultraviolet irradiation device, a commercially available device including a lamp and a light collector for increasing efficiency can be used.

In the present invention, when a large number of filaments are twisted and finished into the string 1, each of the filaments is impregnated with the above-described composite adhesive in advance, and is irradiated with ultraviolet rays while being twisted to cure the impregnated resin in a short time. . In the method of impregnating the ultraviolet curable adhesive after the twisting, the adhesive does not sufficiently penetrate into each filament inside the twisted bundle, and therefore, the filaments do not adhere with sufficient strength. For this reason, the durability of the string cannot be obtained.

As a second step treatment, the filament at the center is cured and fixed by leaving it at room temperature for 1 hour or more.
Achieved by being characterized by coating. If left at a temperature higher than room temperature, the standing time can be shortened.

Finally, a resin having a thickness of 30 μm or more and 150 μm or less after drying is coated by an ordinary method in order to improve the durability at the time of stretching and hitting the ball. As the resin in this case, nylon, polyurethane or the like is desirable from the viewpoint of durability.

Furthermore, when a whisker made of aluminum borate or the like is blended in the coating resin, the durability is further improved. Further, a smoothing agent composed of waxes, silicone oil, or the like is applied to obtain a final product.

[0050]

The present invention will be described more specifically with reference to specific examples. In the following examples, "parts" means "parts by weight". In the durability test, various strings were stretched on a carbon fiber reinforced resin racket having a face area of 110 square inches with a tension of 60 lbs each in the vertical and horizontal directions, and an actual tennis ball was struck out onto the racket at a speed of 127 km / hour. Striking was continued at a launch interval of 15 times / min and a launch distance of 50 cm until the string was cut, and this value was evaluated.

[0051]

EXAMPLE 1 Using the apparatus shown in FIG.
Denier, multifilament of nylon 12 having 1224 single yarns can be anaerobically polymerized in an untwisted state by 84 parts of ultraviolet curable adhesive mainly composed of ultraviolet curable polyurethane acrylate, monomer and photoinitiator. A composite adhesive for an inner layer comprising 16 parts of an anaerobic adhesive containing tetraethylene glycol dimethacrylate as a monomer, cumene hydroperoxide as a polymerization initiator as a latent catalyst, and benzoquinone as a polymerization inhibitor was impregnated. It was passed through a 1 mm nozzle and squeezed. The adhesion amount of the inner layer composite adhesive was 32.7% by weight on a dry weight basis.

Thereafter, while being twisted at a twist number of about 80 turns / m, ultraviolet rays were irradiated using a 4 kW high-pressure mercury lamp and 80 W / cm to cure. Then, it was left at room temperature for 1 hour, and the anaerobic adhesive in the center was cured and the diameter was 1.14 mm.
Was obtained.

The outer periphery of this linear body was coated with hot-melt nylon 66 by a conventional method, and a dimethyl silicone oil dispersion was further applied to obtain a racket string. The adhesion amount of nylon 66 was 23.9% by weight on a dry weight basis. For reference, the adhesion amount of the inner layer composite adhesive at this stage was 23.3% by weight when the whole string was a parameter.

The stretchability of the string on the tennis racket was good with moderate tension and waist. The durability test results are as shown in Table 1, which was better than Comparative Example 1.

The obtained racket string had a diameter of 1.314 mm, a tensile strength of 76.4 kg, and a knot strength of 4
0.3 kg and elongation were 19.8%. The thickness of the coating layer was 85 μm.

[0056]

Example 2 The coating of the linear body of Example 1 above using hot-melt nylon 66, except that a 7% by weight whisker made of aluminum borate was added to hot-melt nylon 66 when coating. Obtained a racket string in the same manner as in Example 1.

The string had good tension and tightness on the tennis racket, had better smoothness, and was even better than the string of Example 1. The durability test results are as shown in Table 1, which was better than Comparative Examples 1 and 2.

[0058]

Comparative Example 1 Example 1 was repeated except that only the ultraviolet-curable adhesive was used instead of the composite adhesive used in Example 1 above.
A racket string was obtained in the same manner as described above.

[0059]

Comparative Example 2 The procedure of Example 2 was repeated except that only the ultraviolet curable adhesive was used instead of the composite adhesive used in Example 2 above.
A racket string was obtained in the same manner as described above.

[0060]

Reference Example A durability test was performed using a monofilament (diameter: 1.307 mm) string of the most typical synthetic fiber (Synsatech) commercially available.

[0061]

[Table 1]

As is clear from Table 1, the string of Example 1 exhibited twice or more the durability as compared with the string cured with only the ultraviolet curable adhesive (Comparative Example 1). The string of Example 1 has almost the same durability as the conventional monofilament string (reference example), but has remarkably excellent hitting properties, and is soft and gives the player a pleasant hit feeling. Further, in the string of Example 2, since the whisker made of aluminum borate was added to the surface resin coating layer, it was confirmed that the durability was further improved.

[0063]

As described above, in the present invention, in a racket string comprising a multifilament of synthetic fibers and having a resin coating layer on the surface, each filament is blended with an ultraviolet curable adhesive and an anaerobic adhesive. Since the string is fixed with the composite adhesive, both the surface layer and the center layer of the string are sufficiently cured and fixed. For this reason, the durability and the knotability of the string can be made and improved by the monofilament of the most typical synthetic fiber (Synsatech) at present.

When whiskers or particles made of aluminum borate are added to the resin coating layer, durability and stretchability are further improved. As a result, a racket string having an excellent feel at impact, being softer, and having excellent durability and stretchability has become possible.

The manufacturing method of the present invention can efficiently and rationally manufacture the string of the present invention.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a racket string according to an embodiment of the present invention.

FIG. 2 is a process step diagram illustrating an embodiment of the manufacturing method of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Racket string 2 Surface part of multifilament 3 Center part of multifilament 4 Inner layer resin applied when twisting multifilament 5 Surface resin coating layer 10 Filament unwinding process 11 Thread package (winding body) 12 Multifilament 13 Guide 14 Multi-filament yarn in a non-twisted state 20 Step of applying inner layer resin 21, 22, 23, 24 Guide 25 Nozzle 26 Resin solution tank 27 Inner layer adhesive composition 30 Ultraviolet or radiation irradiation step 31 Lamp house 32 High pressure mercury lamp 33 Twisted multifilament yarn 40 Twisting and winding process 41 Rotary shaft 42 Twisting / winding machine 43 Guide roll 44 Winding roll 45 Twilling roll 46 Multifilament yarn in which the adhesive on the surface layer is hardened

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-23551 (JP, A) JP-A-7-148285 (JP, A) JP-A-9-31785 (JP, A) JP-A-7-178 96052 (JP, A) JP-A-9-38245 (JP, A) JP-A-2000-167088 (JP, A) Japanese Utility Model Application Sho 62-192755 (JP, U) (58) Fields investigated (Int. Cl. ⁷⁾ D02G 1/00-3/48 D02J 1/00-13/00 A63B 51/00-51/16

Claims (20)

(57) [Claims] 1. A racket string in which a synthetic fiber multifilament is fixed by an inner layer resin and a surface of which is coated with a resin coating layer, the inner layer resin fixing the multifilament is an ultraviolet or radiation curable adhesive. And an adhesive composition comprising an anaerobic adhesive. 2. The racket according to claim 1, wherein the adhesive composition of the inner layer resin comprises 30 to 95% by weight of an ultraviolet or radiation curable adhesive and 5 to 70% by weight of an anaerobic adhesive. String. 3. The adhesive composition of the inner layer resin is composed of a radiation-curable adhesive: 70 to 90% by weight, and an anaerobic adhesive: 10
The racket string according to claim 1, which is composed of about 30% by weight. 4. The racket string according to claim 1, wherein the anaerobic adhesive is a composition containing a methacrylate compound as a main component. 5. The adhesion amount of the adhesive composition of the inner layer resin is in the range of 15 to 35% by weight of the entire string.
The racket string described in 1. 6. The racket string according to claim 1, wherein the resin coating layer on the surface is a nylon resin. 7. The adhesion amount of the resin coating layer on the surface is:
The racket string according to claim 1, wherein the amount is in the range of 15 to 45% by weight of the entire string. 8. The racket string according to claim 1, wherein an inorganic filler is added to the resin coating layer on the surface in a range of 1 to 30% by weight. 9. The racket string according to claim 8, wherein the inorganic filler is in the form of whiskers or particles. 10. An inorganic filler in the form of whiskers or particles of aluminum borate, and 3 to 1
The racket string according to claim 8, which is contained in an amount of 5% by weight. 11. The racket string according to claim 1, wherein the multifilament made of synthetic fibers is a polyamide-based synthetic fiber. 12. A method for producing a racket string in which a multifilament of synthetic fibers is fixed with an adhesive and a surface is coated with a resin coating layer, wherein the multifilament is provided with an ultraviolet- or radiation-curable adhesive, and anaerobic. An adhesive composition containing an adhesive is applied, the multifilament is twisted, and ultraviolet or radiation is irradiated as a first-stage curing treatment to cure the adhesive portion close to the string surface layer, and then the second curing treatment is performed. A method of manufacturing a racket string, comprising curing an adhesive portion inside a string as a step-wise curing treatment, and thereafter applying a coating resin to the surface to form a resin coating layer. 13. The method for manufacturing a racket string according to claim 12, wherein the second-stage curing treatment is a treatment in which the curing treatment is left at room temperature for one hour or more. 14. A method of applying an adhesive composition for fixing a multifilament, twisting the multifilament, and performing a first-stage curing treatment, comprises impregnating the non-twisted multifilament into the adhesive composition. 13. The method for producing a racket string according to claim 12, wherein the multi-filament is twisted and the first-stage curing treatment is continuously performed until the multi-filament is wound. 15. The racket according to claim 14, wherein a multifilament is impregnated with the adhesive composition and then squeezed to adjust the adhesion amount of the adhesive composition to a range of 20 to 40% by weight. Manufacturing method of string for use. 16. The method for producing a racket string according to claim 12, wherein the anaerobic adhesive is a composition containing a methacrylate compound as a main component. 17. An adhesive composition comprising an ultraviolet- or radiation-curable adhesive and an anaerobic adhesive contains 30 to 95% by weight of an ultraviolet- or radiation-curable adhesive, and 5 to 70% by weight of an anaerobic adhesive. The method for producing a racket string according to claim 12, wherein the string is composed of%. 18. The method according to claim 12, wherein an inorganic filler is added to the resin coating layer on the surface in a range of 1 to 30% by weight.
3. The method for producing a racket string according to claim 1. 19. The method according to claim 12, wherein the resin coating layer on the surface is a nylon resin. 20. The method according to claim 12, wherein the synthetic fiber multifilament is a polyamide synthetic fiber.